The pace of astronomic discovery, said the Astronomer Royal, keeps increasing with the constant improvement in our sensing technology. The recent discovery of the accelerating expansion of the universe (dark energy) revolutionized cosmology, and with the launch of the Kepler Telescope in 2009, we are beginning to detect and study Earth-sized planets around distant stars.

Since the Moon landings, humans in space have done little of scientific interest, but unmanned probes have delivered revelations from the planets and moons of the solar system, with much more to come. The best prospects for finding life elsewhere in our solar system appear to be…